The present invention relates to an actuation unit articularly for Venetian blinds or the like.
Currently available double-glazing units are particularly appreciated for their functional properties in terms of heat and sound insulation.
Double-glazing units, in particular, are casements comprising a perimetric frame which supports two parallel panes which are at least partially transparent to light and form, between them, a hermetic air space which contains light blocking means (Venetian blinds, pleated curtains, or the like) which are moved from a fully packed or rolled-up condition to an opened-out condition suitable to provide the light blocking, and viceversa, by motor means associated with the frame.
In particular, the air space between the two panes is hermetic, so as to enhance the heat and sound insulation qualities.
Blocking means, such as shutters, roll-up blinds, Venetian blinds or other equivalent means, can also be accommodated within said air space.
One of the main problems of double-glazing units is to transmit the motion of the motor means to the kinematic systems for moving the blocking means without compromising the hermetic seal of the frame of said double-glazing unit.
Electromagnetic couplings have been conceived for this purpose which are arranged partly inside the double-glazing unit and partly outside it and are substantially constituted by two facing shaft sections which support mushroom-like expansions constituted by disk-like permanent magnets.
In particular, the magnets face each other in the active condition, so as to close axial magnetic field lines.
The electromagnetic couplings, although solving the problem of hermetic sealing, are not free from drawbacks.
First of all, the forces produced by the magnetic field and by the intrinsic structure of the couplings forces them to require, at the ends of the shaft sections, thrust bearings which further complicate the general structure, which in any case must be installed inside the frame of the double-glazing unit, which usually has small dimensions and therefore a limited containment capacity.
It is also known that the force transmitted by the magnetic couplings varies proportionally to the facing surface which is perpendicular to the closed field lines; accordingly, it is evident that in order to increase the force that can be transmitted by the coupling it is necessary to provide magnets having larger radial dimensions.
On the other hand, the seats of the magnets are scarcely able to cope with radial increases in their dimensions, since they indeed have a mainly longitudinal extension.
It is also known that Venetian blinds, to be applied to windows or at door-windows of balconies, are currently also widely used.
Obviously, Venetian blinds and all similar blinds are fixed at the inner face of the window.
If a building is provided with double glazing, which is particularly appreciated owing to its functional properties in terms of heat and sound insulation and is constituted by a first external window, fitted on the exposed face of the building, and by a second inner window, the blinds are preferably arranged in the air space formed between the windows.
Venetian blinds, pleated blinds, shutters and all other similar blinds are light blocking means which must be actuated for movement from a fully packed or rolled-up condition to an opened-out condition.
Currently there is a tendency in the market to prefer motorized actuation systems for blinds, particularly for structures such as offices, hospitals, shopping centers, and if it is necessary to move armored shutters, since they are very heavy.
One of the main problems observed, however, is the transmission of the movement of the motor to the kinematic system for moving the blind so as to contain the bulk.
Moreover, the actuation unit should have a simple and functional structure so as to allow to replace the motor if necessary.
The motor in fact tends to break and malfunction and may require maintenance.
Up to now it has been necessary for a specialized person to act directly to disassemble the motor from the kinematic system and, once the motor has been repaired or replaced, to reinstall it and restore its connection to the kinematic system, with evident complexity in maneuvering and with a great waste of time.